Re: [PATCH v8 0/8] mm: Hot page tracking and promotion infrastructure

[Yongting Lin]

On Mon, Aug 10, 2026 at 07:37:05AM -0700, SJ Park wrote:
> [...]
> > IBS is not the only possible hardware source. CXL 3.2 defines CHMU for
> > device-side hotness monitoring, and CHMU has also been discussed in the
> > DAMON and CXL hotness-monitoring discussions.
>
> Yes, we discussed DAMON could be extended for access check primitives other
> than page table accessed bit, and CHMU could be one of such primitives.  The
> extension is in progress [1].

Thanks for the pointer. I will take a closer look at the series.

> [...]
> > We would also be interested in helping test and compare the different
> > approaches as implementations become available.
>
> Please feel free to let me know if you want to test DAMON-based approaches.  I
> will be happy to help :)

Yes, we would be interested in testing this on our CXL tiered-memory
systems.

I previously built a Redis workload with controlled hot and cold memory
regions, and compared DAMON's results with those reported by a WSS tool.
The estimated hot and cold memory sizes differed substantially. I
understand that DAMON and the WSS tool have different semantics, and it
is also possible that my DAMON parameters were not optimally tuned.

Once hardware-based monitoring becomes available, I would also like to compare
DAMON's page-table accessed-bit monitoring with PMU- and CHMU-based access monitoring.

Thanks,
Yongting